Combined coal and gas furnace



April 15, 1930. L, SHARP 1,754,405

COMBINED COAL AND GAS FURNACE Filed April 19, 1929 2 SheetsSheet 1 ll i25 1 2 8 i 4m 25 z/ J 7 2 EI/fl 19 7 /a 4 j: {a 619i 4-0 35 lllgwvcantoc loaid 6. 4247 11.

dummy April 15, 1930.

' 2 Sheets-Sheet 2 Filed April 19, 1929 6 z a, W. a 1 z 5 ll j INH 3 w 67 I i 5 5 m 1 W Patented Apr. 15, 1930 UNITED STATES LOUIS n. SHARP, on

PATENT OFFICE DENVER, COLORADO comnmnn cont AND ens summon Applicationfiled April 19,

residences is becoming very general andin many places the ordinary coalfurnace isemployed by merely substituting a gas burner for the grate.Such converted furnaces are not entirely satisfactory because if thefurnace is properly designed for burning coal, it will not operate asefficiently with gas as itwould if it were designed with particularreference to this type of fuel. It is well known that when coal isemployed for fuel, there is a gradual accumulation of soot and dustwithin the flues through whichthe gases of combustion pass and thefurnace has to be designed in such a way that a large amountof thismaterial can be collected without interfering seriously with the draftand operation of the furnace. The fact that coal produces a soot depositas above mentioned, makes it necessary to have the flue passages shorterand straighter than they would have to be if a fuel Were used that didnot produce such deposits. When gas is employed, there is very little,if any, soot or other material deposited on the inside of the furnaceand it is therefore possible to have longer and more 5 tortuous fluepassages and by this means the a 1929. Serial No. 356,382.

whereby adjustments can be made in the areas of the flue passages, so asto make the furnace suitable for either type of fuel.

a It is another object of this invention to produce a furnace that shallhave an exceptional- ,0

1y large radiation surface in comparison with its size so that the heatproduced by the fuel will be as completely as possible transferred tothe surrounding a1r.

It is a still further object of this invention to produce a furnacewhich shall be so designed and constructed, that it will have amplespace for the hot air to pass through the interior of the furnace shelland which will direct the passage of the air in such a way 0 that all ofthe air will come in contact with the heated surfaces of the furnace soas to secure an efiicient and complete transfer of heat fromthe furnaceto the air.

The above and other objects which may appear as the description proceedsare attained by means of a construction and an arrange ment of partsthat will be described in detail, reference for this purpose being hadto the accompanying drawings in which the pre- 7 ferred embodimentthereof has been illustrated, and in which:

Fig. 1 is a vertical section through the furnace.

Fig. 2 is a transverse section taken on line 2--2, Fig. 1;

Fig. 3 is a section taken on line 3 3, Figs. 1 and 4, and shows the tworadiator sections;

Fig. 4 is a section taken on line 4-4, Fig. 3,

parts of the radiator section being broken 30' away;

Fig. 5 is a section similar to that shown in Fig. 1, but showingthe gasburner removed and replaced by a water pan for moistening the air; and

Fig. 6 is a section taken on line 6-6, Fig. 5.

In the drawings reference numeral 1 represents the ash pan section ofthe furnace on which the combustion section is supported. Thiscombustion section has a cylindrical 90 portion 2 which forms the wallof the fire pot and whose upper edge is outwardly flared so as toprovide an inclined flange 3 whose outer edge terminates in an upwardlyextending roove 4, for the reception of the wall memher 5, which is madein the form of a ring. The upper end of section 5 is provided with aroove 6 in which the lower edge of the raiator section 7 rests. Thisradiator section has an inwardly curved upper end portion 8 whichterminates in a downwardly extending circular wall 9. A crown plate ordome 10 is supported by the upper ends of the tubes 11. These tubes havetheir lower ends connected with the upwardly extending tubular nipples12 and have their upper ends connected with similar downwardly extendingnipples 13, which are formed integral with the dome. The central part ofthe dome is preferably concave on its upper surface and convex on itslower surface, but may be straight or upwardly curved. The dome memberis provided with a downwardly inclined flange 14 whose outer edgeterminates a short distance from the inner surface of wall 7. Thisflange is provided with a plurality of spaced notches 15 and supports aring-like member 16, which is also provided with a plurality of notchescorresponding in number and position with the notches 15. When the ringis rotated, it can be moved into such a position that the solid portionsoverlap the notches 15, or into such a position that the notches 15 areentirely uncovered. The upper surface of flange 14 is provided with alug 17 that'serves as a stop and which limits the rotary movement ofmember 16. A handle 18 is secured to the ring 16 and serves as aconvenient means for rotating the ring. A clean-out opening 19 isprovided in the radiator section 7 directly in front of handle 18 sothat a proper tool may be in sorted into this opening for rotating thering. The object and function of this ring will be more clearlyexplained as the description proceeds. The curved part 8 of the radiatorsection 7 is provided with two diametrically spaced upwardly projectingcircular nipples 20 with which the nipples 21 that are secured to thelower surface of the radiator section 22 cooperate for holding thelatter section in place and for connecting its interior with theinterior of radiator section 7. The upper surface of the annularradiating section is provided with two upwardly extending circularnipples 23 which are adapted to receive the downwardly extending nipples24 of the flue radiator 25. One end of this flue radiator is providedwith a hinged door 26 and the other end is connected with the flue 27"which extends to the Smokestack or chimney.

The annular radiator section 22 is provided with two diametricallylocated partitions 28 which divides the interior thereof into twoseparate compartments in the manner indithe manner shown in Fig. 0.

cated quite clearly in Fig. 4. The flue gases enter this radiatorsection through openings 29 and after passing half ways around thesection leave through the openings 30, from which they pass into theflue radiator 25. Clean-out openings 31 are provided at opposite sidesof the radiator section.

This furnace is provided with a recess which has been designated by Aand which is located directly beneath the door 32 of the combustionchamber and above the wall 33 of the ash chamber. When the furnace isused with coal, this recess serves as a chamher in which the water pan34 is located in If the furnace is to be used with as fuel, the pan 34is removed and replaced by a gas burner which has been shown in Fig. 1and which has been designated by reference numeral 35. The wall 2 of thefire pot is provided with an opening 36 of the proper size to receivethe inner end of the gas burner. \Vhen the gas burner is removed, orwhen the furnace is used with coal as fuel, a plate 37 is put in placein the opening 36 in the manner shown in Figs. 5 and 6. When the furnaceis used with gas the water pan 34 is moved to the location shown in Fig.1 so that it will not interfere with the operation of the furnace. Thefurnace is provided with a grate 38 which can be in place even when thefurnace is operated by means of gas and therefore the change from gas tocoal, or from coalto gas, can be readily made. When the furnace is usedwith gas as fuel, the ring 16 is rotated into such a position that itcovers the openings 15 and there is then left a narrow annu-- lar spacebetween the inner surface of the wall 7 and the outer edge of ring 14through which the gases must pass. This throws the heated gasesoutwardly against the outer surface of the radiator section and bringsthem into close contact therewith, so that a good heat exchange takesplace. WVhen gas is used for fuel there is, as above explained, verylittle if any soot deposited in the flue chambers, but whencoal is useda lot of soot is formed and deposited. When coal is employed, theannular space about the outside of rim 14 soon becomes filled so as todestroy the draft and it is therefore necessary when changing from gasfuel to coal to move the ring 16 to such a'position that the notches inthis ring register with the openings 15 and by this means largeropenings are produced through which the gases of combustion pass andthis prevents the clogging due to the accumulation of soot. In order tokeep the space about ring 14 clean. I have provided ring 16 with aplurality of downwardly extending lugs 39 that project over edge of theflange and serve to wipe the soot away fro-m these edges when the ringis rotated.

When the furnace is in operation, the heated air passes from wit-hin'theshell 40 to the the outside of the combustion chamber and around andabout the radiator sections and absorb the heat from the latter. Owingto the big area of the air'passages, the furnace has a free circulationof air and at the same time brings the air into such close contact withthe walls of the furnace that it will quickly attain a high temperature.

In the above description gas has been men tioned as the fuel that can beemployed in the place of coal, but it is evident, however, that oil maybe used as well as gas.

Having described the invention what I claim as new is: V

1. A furnace having a fire pot, formed in part by a cylindrical member(5) and a dome member (10), said dome member having its outer edge inclose proximity to but spaced from the inside of thecylindrical memberwhereby an annular passage is formed for the passage of flue gases, saiddome member having its outer edge provided with openings and means forvarying the effective area of said openings.

2. A furnace having a fire pot, formed in part by a cylindrical member(5) and a dome member (10), said dome member having its outer edge inclose proximity to but spaced from the inside of the cylindrical memberwhereby an annular passage is formed for the passage of flue gases, saiddome member having its outer edge provided with openings and means forvarying the effective area of said openings, said means comprising aring provided with openings adapted to register with the openings in thedome member when in one position and with solid portions adapt ed toform closures for the openings when the ring is in another position.

3. A furnace having a fire pot, formed in part by a cylindrical member(5) and a dome member (10), said dome member having its outer edge inclose proximity to but spaced from the inside of the cylindrical memberwhereby an annular passage is formed for the passage of flue gases, andmeans for removing accumulations of soot from said passage.

4:. A furnace having a fire pot, formed in part by a cylindrical member(5) and a dome member (10), said dome member having its outer edge inclose proximity to but spaced from the inside of the cylindrical memberwhereby an annular passageis formed for the passage of flue gases, andmeans for removing accumulations of soot from said passage, said meanscomprising a ring adapted to rest on the upper surface of the domeadjacent the edge thereof and a plurality of lugs secured to the ring,said lugs projecting downwardly into the passage whereby when the ringis rotated about its center, the lugs will clean the passage. i r a 5. Afurnace having a fire pot formed from a cylindrical member (2) whoseupper end terminates in an outwardly extending flange (3), said flangehaving a plurality of spaced openings, a dome member having openingscorresponding in number and position with the openings in the flange,tubular members extending from the upper surface of the flange to theunder surface of the dome, said tubular members being in axial alignmentwith the openings, a cylindrical member (5) supported on the flange andextending above the dome, the upper end of this member being curvedinwardly and thence downwardly, and having its edge resting on the uppersurface of the dome, the diameter of the dome being slightly less thanthe inside diameter of the cylindrical member, but larger than theinside diameter of the downwardly extending upper portion whereby anannular chamher is formed that is in communication with the fire potthroughthe passage about the outer edge of the dome, an annular hollowradiator section supported from the upper curved end of the ring-likemember and connected with the interior of the latter and a flue sectionconnected with the interior of the annular radiator section.

6. A furnace having a fire pot formed from a cylindrical member (2)whose upper end is flared outwardly so as to form a flange (3), an ashreceptacle section located underneath the cylindrical member andeccentric with respect thereto, the lower end of the cylindrical memberhaving an opening, a gas burner resting on the uppersurface of the ashreceptacle, the end of the burner extending inwardly into the openinggaradiator section located above the fire pot, means for deflecting fluegases outwardly against the inner surfaces of the radiator section, andmeans for varying the effectiveness of the deflecting means.

7. A furnace having a fire pot formed in part by a cylindrical member(2), whose up per end is flared outwardly so as to form a flange (3), acylindrical wall member resting on the upper surface of the flange, theupper end of said wall member being inwardly and downwardly curved, adome member located above the upper surface of the flange with its uppersurface inv contact with the lower end of the downwardly extending endof the upper part of the cylindrical member, a plurality of tubularsupports extending from the flange to the dome and serving as supportsfor the latter, the diameter of the dome being greater than the diameterof the downwardly extending portion of the cylindrical wall member andsomewhat less than the inside diameter of the cylindrical wall memberwhereby an annular passage is formed between the combustion chamberbelow the dome and the compartment above the dome, the edge of the domehaving a plurality of radially spaced openings, and a ring supported onthe dome and movable with respect thereto, said ring having openingsadapted to register with the openings in the dome when in one positionand solid portions adapted to close the openings When in anotherposition.

In testimony whereof I aifix my signature.

LOUIS E. SHARP.

